Laser gas-assisted nitriding of Ti implant

Purpose - The purpose of this paper is to investigate the morphological and metallurgical changes of laser gas-assisted nitriding of titanium implants. Design/methodology/approach - Laser gas-assisted nitriding of titanium implant is carried out and the metallurgical as well as the morphological changes in the nitride layer are examined using optical microscopy, SEM, XRD, and X-ray photoelectron spectroscopy. Temperature and thermal stress fields are computed during the laser heating process adopting the finite element method. The residual stress formed in the nitride layer is measured using the XRD technique while micro-indentation tests are carried out to determine the fracture toughness of the surface after the laser treatment process. Findings - It is found that nitride depth layer extends to 40 mu m below the surface and it is free from the cracks and micro-voids. The residual stress formed on the surface region is higher than at some depth below the surface in the nitride layer, provided that the maximum residual stress is less than the elastic limit of the substrate material. Originality/value - The paper contains original findings and the findings are not submitted any other journal for publication.